Drill press



DRILL PRESS Filed July 15, 1935 i INV ENT OR.

ATTORNEY.

Patented Mar. 16, 1937 UNl'l'ED STATES PATENT OFFlCE I DRILL PRESSWalter G. Mitchell, Oak Park, ill.

ApplicationJuly 13, 1935, Serial No. 31,138

I i Glaims. (or. 74 -217) This invention relates to drill presses andparticularly-to drill presses of the type run by belt drive fromindividual motors so that the drills are driven at comparatively highspeeds.

The objects of the invention are: N

First, to produce a drill press having a change speed mechanism that issuitable for use primarily in reducing the speed at which the spindleofthe press is driven to permit the use of larger size drills at speedswhich will reduce or eliminate the excessive heating which draws thetemper of the drill and reduces its usefulness.

Second, to produce such a change speed mechanism that may be madeinexpensively and may 15 be easily installed upon drill presses of thetype set forth above.

Third, .to produce such a change speed device that is in the nature ofan attachment.

Further objects and advantages pertaining to 'details and economies ofconstruction and operation will appear from the description to follow.

A preferred embodiment of the invention is illustrated in theaccompanying drawing, in which:

' Fig. 1 is a view in elevation of the side of the upper portion of adrill press embodying my invention.

Fig. 2 is a sectional view through the intermediate pulley of my changespeed mechanism. Fig. 3 is a sectional plan view taken on lines 3 3 ofFigs. 1 and 2. I

. Fig. 4 is a perspective view of an expansion plug used in my improvedapparatus.

Fig. 5 is a detail sectional view of a slightly 35 modified form of mydevice. V

In the drawing, i represents the column of a drill press, and 2 the headwhich is split as indicated at 3 and t to clamp the column l. v5 is abolt for clamping the split head in'position on 40 the column. 6 is thespindle, l the quill and 8 the chuck.

9 is the driving motor supported on the support H] which consists of asapporting member I I having parallel rods l2 extending therefrom andpro- 45 vided with a threaded portion l3 engaging a screw M having ahand wheel l5 thereon. Bearing.

members llll also engage the screw, so thatby turning the hand wheel I5the motor 9 may be raised or lowered to desired position.

The rods l2 extend through .sockets l2! on the sides of the head and areheld in place by 'set screws I22 provided with thumb grasps I23.

By loosening the set screws I22, the motor mayv 55 be pushed toward oraway from the column, as

will be obvious, and may be nxed in position by tightening the screwsl22.

The motor is provided with a multi-step pulley B6 of the V-belt typehaving its axis arranged vertically. The spindle 6 is provided with asim- 5 ilar multi-step pulley Ill arranged on a vertical axis. Thepulley i6 is a driving pulley and the pulley l'l is a driven pulley inthe arrangement according to my invention.

Thecolumn l as shown is tubular in form 10 so that the top portion has ahollow cylindrical portion l8. i9 is an expansion plug adapted'to fitandlrotate in'the hollow portion I8 of the top of the column I. It willbe appreciated that instead of having a hollow column in which a plug isfitted, a cap 5|] may be employed fitting over the top of the column andheld by' a set screw 5|, as shown in Fig. 5. On this may be mounted themulti-step pulley hereinafter described and which may be arranged to beclamped to the top of the column as will be readily understood. t

.The expansion plug is is split at 20 and the lower portion of the slotat 20 is made with the sides diverging downwardly as at H. A bore 22meets the diverging portion 2! and a bolt 23 passing through the borehas its head 2t engaging the diverging sides 2| and is provided with anut 25 and washer 26, so that a tightening of the nut 25 forces the head2t between the diverging walls to expand the plug and clamp it firmly indesired position in. the hollow portion it at the top of the column I.

Arms 21 extend upwardly from the plug 09 and support eccentrically ofthe axis of rotation v of the plug it! a bearing 28 which is arranged toreceive a vertical shaft 29 on which a multi-step pulley 30 is keyed orotherwise fastened.

It will be noted that in the particular embodiment of my invention shownthe multi-stage pulleys i6 and ii are of the conical type having thesmallest pulley at the top, whereas the pulley 30 is of the same typehaving the smaller pulley at the bottom. It will be understood that thepulley H is splined to the spindle 6 to permit the spindle to be movedthrough the pulley H in feeding the drill.

A belt 3! extends from the. driving pulley IE to the pulley 30 and abelt 32 extends from the intermediate pulley-30 to the driven pulley I1,so that in the arrangement shown in full lines in Fig. -1 the spindle isdriven at a'slow speed. With the belts arranged as is shown by thedotted lines in Fig. 1,- of course, the speed of the spindle would begreatly increased.

stages of the pulleys IS, IT, and 30, this is accomplished by looseningthe set screws I22 to move the motor toward the column. This loosens thebelt 3i and permits its removal if desired.

The nut 25 may then be loosened and by rotating the plug l9 about itsvertical axis the pulley 30 is swung toward or away from the pulley I].In loosening the belt 32 as shown in Fig. 1. the pulley 30 would beswung toward the pulley I! as will be appreciated. The belts can be thenrearranged and the plug i9 rotated to swing the pulley 30 away from thepulley I! to tighten the belt. The nut 25 is then tightened to expandthe plug i9 and fix it in desired position. Of course, if a cap is usedinstead of a plug, it may be contracted to clamp the top of the columnor provided with other means for holding it rigidly in position at thedesired adjustment. The motor 9 is then moved away from the column i andis fixed in its desired position by means of the set screws I22.

In the particular arrangement shown, the plug I9 can be supplied withthe pulley 30 thereon as an attachment for standard drill presses havingcolumns with hollow tops and the particular arrangement of driving motorand spindle. the addition of belts 3i and 32 making a completeconversion of a high speed drill press to a lower speed drill press. Itis also possible, as has been pointed out, to have a hollow cap providedwith the pulley 30 to serve as an attachment to fit over the top of thecolumns of standard drill presses.

I have shown a preferred embodiment of my invention and wish to claimthe same specifically and also broadly as pointed out in the appendedclaims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. In-a drill press, the combination of a vertical column with a hollowupper end, a drill head on said column and having a drill spindle with adriven multi-step pulley therefor disposed on a vertical axis, a drivingmotor having thereon a multi-stcp driving pulley disposed on a verticalaxis, a support for said driving motor and driving pulley, means foradju'stably moving said support to or away from said column. anexpansion plug fitted in and rotatable about a vertical axis in thehollow end of said column, means for expanding said expansion plug tofix it in desired position, an intermediate. multi-step pulley disposedon a vertical axis eccentric to the axis of rotation of said, plug.whereby rotation of said plug will vary the distance between the'axis ofsaid intermediate pulley and the axis of said driven pulley, a beltconnecting said intermediate pulley with said driving pulley, and asecond belt If it is desired to change the belts to different connectingsaid intermediate pulley with said driven pulley.

2. In a drill press, the combination of a vertical column with a hollowupper end, a drill head on said column and having a drill spindle with adriven pulley therefor disposed on a vertical axis, a driving motorhaving thereon a driving pulley disposed on a vertical axis, a supportfor said driving motor and driving pulley, means for adju'stably movingsaid support to or away from said column, an expansion plug fitted inand rotatable about a vertical axis in the hollow end of said column,means for expanding said expansion plug to fix it in desired position,an intermediate multi-step pulley disposed on a vertical axis eccentricto the axis of rotation of said plu whereby rotation of said plug willvary the distance between the axis of said intermediate pulley and theaxis of said driven pulley, a belt connecting said intermediate pulleywith said driving pulley. and a second belt connecting said intermediatepulley with said driven pulley.

3. In a drill press, the combination of a vertical column with a hollowupper end, a drill head on said column and having a drill spindle with adriven multi-step pulley therefor disposed on a vertical axis,. adriving motor having thereon a multi-step driving pulley disposed on avertical axis, an expansion plug fitted in and rotatable about avertical axis in the hollow end of said column, means for expanding saidexpansion plug to fix it in desired position, an intermediate multi-steppulley disposed on a vertical axis eccentric to the axis of rotation ofsaid plug, whereby rotation of said plug will vary the distance be- Itween the axis of said intermediate pulley and the axis of said drivenpulley, a belt connecting said intermediate pulley with said drivingpulley, and a second belt connecting said intermediate pulley with saiddriven pulley.

4. In a drill press, the combination of a vertical column with a hollowupper end, a drill head on said column and having a drill spindle with adriven pulley therefor disposed on a vertical axis, a driving motorhaving thereon a driving pulley disposed on a vertical axis, anexpansion plug fitted in and rotatable about a vertical axis in thehollow end of said column, means for expanding said expansion plug tofix it in desired position. an intermediate multi-step pulley disposedona vertical axis eccentric to the axis of rotation-of said plug, wherebyrotation of said plug will vary the distance between the axis of saidintermediate pulley and the axis of said driven pulley, a beltconnecting said intermediate pulley with said driving pulley, and asecond belt connecting said intermediate pulley with said drivenpulley;.

WALTER G. MITCHELL.

